GB2278554A

GB2278554A - Rotary atomiser for a food flavouring system

Info

Publication number: GB2278554A
Application number: GB9310817A
Authority: GB
Inventors: Derek Edwin Snelgrove
Original assignee: ITW Ltd
Current assignee: ITW Ltd
Priority date: 1993-05-26
Filing date: 1993-05-26
Publication date: 1994-12-07
Anticipated expiration: 2013-05-26
Also published as: GB9310817D0; GB2278554B

Abstract

A rotary atomiser for a food flavouring system is described comprising a housing (1) for a high speed air bearing turbine (2), an axial hollow spindle (3) driven by the turbine (2), a manifold (4) secured to the housing (1) and turbine (2) the manifold (4) having connections (5) for fluid to be sprayed through the hollow spindle (3), (6) for the air to drive the turbine, (7) for shaping air and (8) for the air-bearing air. The front of the housing (1) has a rotary nozzle (10) with an axial hole connecting with the spindle (3). The nozzle (10) has a recessed front face tapering from an axial hole (11) to the nozzle peripheral rim (14) and a cover (15) secured to the nozzle (10) and spaced from the axial hole (11). The rotary atomizer is used to spray coat food snack products e.g. potato crisps, with a food flavouring powder mixed with vegetable oil forming an emulsion. <IMAGE>

Description

ROTARY ATOMISER FOR A FOOD FLAVOURING SYSTEM This invention relates to a rotary atomiser for a food flavouring system.

Rotary atomisers are already known which apply a coating of a fluid material to a surface, such as that used to spray paint to car bodies. These are high speed atomisers for the electrostatic application of conventional and high solids coating materials.

The disadvantage of such rotary atomisers is that the greater the solid content of the coating material, the more liklihood there is of the flow path of the fluid to be sprayed becoming blocked and requiring regular maintenance and cleaning to prevent the atomiser seizing up.

An aim of the present invention is to provide an improved rotary atomiser for spraying fluids containing larger particles without clogging the fluid path.

According to the present invention there is provided a rotary atomiser comprising a housing for a high speed air-bearing turbine, an axial hollow spindle driven by the turbine, a manifold secured to the housing and turbine, the manifold having connections for fluid to be sprayed through the hollow spindle, the air to drive the turbine, shaping air and the air-bearing air, the front of the housing having a rotary nozzle with an axial hole connecting with the hollow spindle, wherein the nozzle has a recessed front face tapering from the axial hole to the nozzle peripheral rim and a cover secured to the nozzle and spaced from the axial hole.

Preferably, the hollow spindle has a sealing ring which prevents the fluid product which exits from the nozzle entering an air passage surrounding the rear of the nozzle.

An embodiment of an improved rotary atomiser, according to the invention, will now be decribed by way of example only, with reference to the accompanying drawings, in which: Fig. 1 is an exploded view of the rotary atomiser; and Fig. 2 is an enlarged detail of the atomiser nozzle.

The rotary atomiser comprises an outer housing 1 within which is located a high speed air-bearing turbine 2 which drives a hollow axial spindle 3 for the fluid to be sprayed. The rear of the housing 1 has releasably secured thereto a manifold 4 for connection to an inlet 5 for the fluid to be sprayed, a connection 6 for the air supply to drive the turbine 2, a connection 7 for a supply of air to shape the fluid supply and a connection 8 for the air to drive the bearing.

The manifold 4 has quick release catches 9 to engage the housing and lock it to the manifold.

The forward end of the atomiser has a bell-shaped rotary atomiser nozzle 10 with an axial hole 11 which is driven at a high-speed of up to 60,000 r.p.m.

As shown in detail in Fig. 2, the bell-shaped atomiser nozzle 10 has a shank 12 which is securely mounted on the forward end of the driven spindle 3 with the interposition of a sealing sleeve 13 to prevent the fluid to be sprayed from entering the air passage. The atomiser nozzle 10 has a bell-shaped recess which tapers from the hole 11 to a peripheral rim 14.

The centre hole 11 is covered by a disc 15 which is spaced from the nozzle by a serrated shoulder 16 and is secured to the nozzle recess by screws 17 to form a radial flow path to the nozzle rim 14 for the fluid to be sprayed. Although a continuous shoulder 16 is illustrated, this may be replaced by a number of spaced serrated shoulders to provide a free outlet path for the sprayed fluid.

The nozzle end of the rotary atomiser has a shaping air ring 18 screwed to a shaping air cap 19 which is in turn secured to the housing 1. A felt muffler 20 is located around the air-bearing turbine 2 to seal the turbine and prevent vibration within the housing l.

The rotary atomiser has a particular use in the spray coating of food snack products, such as potato crisps, with a food flavouring powder mixed with a vegetable oil to form an emulsion.

The internal fluid feed system of the improved rotary atomiser has been developed to prevent any separation of the flavouring powder from the vegetable oil which would cause blocking of a normal fluid coating system. This improved atomiser allows for continuous production to proceed without the need for flushing the atomiser system to remove dry material caused by particle separation from the oil base.

The liquid droplet size of the spray can be controlled using a computer-controlled panel to enable the operator to set the turbine speed, the shaping air, the fluid flow of the coating to be sprayed and other normal control functions. The size of the liquid droplets can thus be varied from large individual droplets to a very fine continuous mist. The fluid flow rates can be varied to suit production requirements or allow for a wet-coating of the food products or a nearly dry application.

The high speed rotary atomiser is driven by dry, clean oil free air at any selected speed from 0 to 60,000 r.p.m. To coat food snack products with a flavour coating, the atomiser is mounted in a rotatable drum into which the food products to be coated are automatically fed. As the products are rotated past the high speed atomiser they are coated by the liquid spray of flavour powder/oil emulsion, which emerges as a round pattern and touches the inside diameter of the rotating drum. All the individual snack products have to pass through the food flavouring spray.

The design of the bell-shaped nozzle allows for the free flow of the liquid flavouring at a very fine disposition and particle size without blocking of the fluid feed system.

A double roller pumping system (not shown) is used to pump the flavoured liquid from a container to the rotary atomiser. The liquid is fed to the manifold at the rear of the atomiser via a plastics hose and is propelled to the atomiser nozzle which rotates at high speed and sprays the flavoured liquid under centrifugal force from the peripheral rim where it enters the space within the rotary drum at a predetermined angle determined by the angle of the nozzle rim. The amount of liquid flow from the atomiser can be selected on the control panel, to suit the flavour coating required, by increasing or decreasing the pump rotation speed.

The shape of the pattern of the liquid spray leaving the nozzle can also be adjusted by setting the turbine speed, which can also be used to increase or decrease the flavouring particle size as required for the particular snack product being coated.

One of the advantages of the improved rotary atomiser is that the fluid feed system is made from stainless steel while the spray nozzle is made from hard anodised aluminium or stainless steel. The fluid feed and air hoses are made from a suitable polyvinyl material which can be easily removed for cleaning.

Claims

CLAIMS:

1. A rotary atomiser comprising a housing for a high speed air-bearing turbine, an axial hollow spindle driven by the turbine, a manifold secured to the housing and turbine, the manifold having connections for fluid to be sprayed through the hollow spindle, the air to drive the turbine, shaping air and the air-bearing air, the front of the housing having a rotary nozzle with an axial hole connecting with the hollow spindle, wherein the nozzle has a recessed front face tapering from the axial hole to the nozzle peripheral rim and a cover secured to the nozzle and spaced from the axial hole.

2. A rotary atomiser as claimed in Claim 1, wherein the hollow spindle has a sealing ring which prevents the fluid product which exits from the nozzle entering an air passage surrounding the rear of the nozzle.

3. A rotary atomiser as claimed in Claim 1 or 2, wherein the cover is disc-shaped and spaced from the nozzle recess by at least one serrated shoulder to allow the passage of fluid product from the hollow shaft to the atmosphere.

4. A rotary atomiser as claimed in any preceding claim, wherein the manifold is releasably secured to the turbine and housing by catches.

5. A rotary atomiser as claimed in any preceding claim, wherein the turbine is sealed in the housing by a felt muffler.

6. A rotary atomiser as claimed in any preceding claim, wherein a shaping air ring is secured to the front of the housing by a shaping air cap.

7. A rotary atomiser as claimed in any preceding claim, wherein the nozzle cover is disc-shaped and is secured to the nozzle by two or more screws.

8. A rotary atomiser as claimed in any preceding claim, wherein it has means to mount it in a rotatable food product drum.

9. A rotary atomiser substantially as herein described and shown in the accompanying drawings.

10. Each and every novel feature or novel combination of features herein disclosed.